1. Field of the Invention
The present invention relates to a system and method of producing medical devices, such as Orthotic and Prosthetic devices, soft good garments and compression hose, facial masks, custom footwear, foot Orthotics and/or other custom goods or devices or volumetric comparisons, and in particular, a system and method of accurately producing medical devices.
2. Description of the Related Art
One of the primary goals in the manufacture of certain medical devices, such as orthotic and prosthetic structures, is to achieve a comfortable and accurate fit for the patient. In order to accomplish this, it is necessary to identify and define the precise shape of the patient's body part to be supported. For example, determining the precise shape of the body part is necessary for the formation of an effective mold, model, or mating part, such as the support socket of a clinical support device. Unfortunately, one cannot necessarily create a device such as an orthotic or prosthetic structure based solely on the shape of the body part to be supported. For example, in the case of an orthotic or prosthetic device, the support device is generally adapted to be fitted over a patient's limb in order to act as either a replacement for the missing limb or a support in the case of a pathogenic limb. This creates a substantial amount of constant pressure being exerted on the limb. However, most portions of the human body are not capable of withstanding constant, focused pressure for extended periods of time. As such, it is necessary to design the support socket in such a manner as to spread the pressure out in order to avoid concentrating pressure on any one portion of the limb. Thus, designing a comfortable and accurate medical device such as this requires a trained practitioner with knowledge of the various sensitivities of patients' body parts, such as a physician, a prosthetist or an orthotist, to make these necessary adjustments.
Currently, the most common way of defining the shape of a body part is by making a mold of the body part by hand. A trained practitioner can then manipulate the mold in order to correctly spread out the pressure to be exerted on the patient. The final shape is then cut by a milling or carving machine so as to form the physical model into a foam or plaster blank. This final foam or plaster shape is then draped in some manner with heated plaster or laminate to create the finished medical support device to be used on the patient. However, this method is prone to deviations caused by human error. Thus, in order to achieve an accurate fit by making a mold by hand, even a highly trained practitioner usually has to make multiple revisions requiring multiple moldings. This is extremely time-consuming and inefficient. Additionally, this method can be very limited in its accuracy.
Another known method of defining the shape of a body part is described by a family of patents by Pratt; including U.S. Pat. Nos. 5,781,652, 6,144,386 and 6,236,743. These patents describe a digitizing system that includes a probe that is placed in contact with the body part to be supported. The probe is structured to provide specific six-degree of freedom position and orientation information relative to a reference element. The position and orientation of the probe relative to the reference element is determined and the volume relative to the reference element through which the probe is passed is determined and stored by the digitizing system so as to determine the shape of a support area of the medical device which engages the body part to be supported. Although this method is faster than molding, it has numerous drawbacks. For instance, when the probe is in contact with a body part, the body part is slightly depressed which can result in inaccurate measurements. Further, similar to the currently known laser scanning methods described in more detail below, this method cannot be used to carve molds of body parts that contain more than one axis. Also, these devices cannot be used when the patient is moving.
Another known method of defining the shape of a body part is by utilizing a laser scanning device. These devices use laser refraction and reflectivity to map out the body part's precise shape and contour. The shape of the body part is then displayed onto a computer screen and can be manipulated using Computer Aided Design (“CAD”) software. This information is then utilized by Computer Aided Manufacturing (“CAM”) software which enables a carving machine to carve an accurate mold of the body part with the practitioner's adjustments. Although this method is more precise than molding by hand, existing systems have many drawbacks. For instance, many prior art systems are only able to track the movement of either the patient or the scanning device. Thus, either patient movement or movement of the scanning device can result in inaccurate scans. Additionally, the amount of information that is necessary to create a shape capable of manipulation by CAD software is relatively large. As such, CAD programs for use in these systems generally must be adapted to accept “high algorithm” software. However, CAM programs are generally “low algorithm” software, as carving machines can only process a relatively small amount of information compared with CAD programs. Thus, typical CAM software cannot accept the high algorithm CAD data necessary to achieve successful molding. Also, although there currently exists CAM programs that are capable of carving multiple axis molds, prior art CAM programs have been unable to utilize scanned images of body parts that contain more than one axis (e.g., an ankle and a foot) for carving. Currently, the CAM programs that can carve molds of multiple axes can only utilize templates of body parts, not actual scanned images. Thus, prior art CAM programs have not been able to achieve precise carving of the images having more than one axis that have been scanned and imported into the CAD program.
There are many additional known methods of defining a body part. For example, U.S. Pat. No. 6,463,351 issued to Clynch describes a method wherein a mold is made of the body part by hand, the mold in then sent to a central fabrication facility which scans the mold by a laser scanning device. The image created by the scanning device is then manipulated to provide the needed areas of build-up and relief. A carving machine to carve the device then utilizes this information. In addition to being incapable of carving actual images of body parts containing more than one axis, this method also has many additional drawbacks. For instance, the practitioner making the initial mold must send that mold to a central facility to be scanned. This can be cumbersome and inefficient. Additionally, the actual body part is not scanned, but rather only an initial mold of the body part is scanned. Such an approach can be prone to human error. Further, only the outside of the initial mold is scanned, which never touches the body part. Thus, any carving from a scanned image of the outside of the mold is at best an educated guess of the actual shape and contours of the body part.
The present invention is directed at a system and method of producing medical devices that overcome shortcomings of the prior art methods.